For example If a 300 Hz sine wave interferes with a 305 Hz sine wave, the resulting binaural frequency will be 5 Hz. The frequency of the binaural tone is equal to the difference between the frequencies of the two sine waves. The two waves represent the left and right channels of a stereo signal, and we say that they are in phase because the peaks and troughs of the two waves are perfectly aligned. Constructive Interferenceįigure 1 shows two sine waves (one of the simplest forms of sound waves) that are perfectly “in phase”. The following diagrams illustrate how wave interference occurs and how this effect can be used to create binaural frequencies. They may interfere with each other in more complex ways, combining to create new sounds that contain harmonics. They may cancel each other out, creating silence (destructive interference), or,ģ. They may add to each other to create a louder sound (constructive interference).Ģ. Air pressure waves created by two separate speakers will interfere with each other in one of three ways:ġ. The speed of movement of the speaker is directly proportional to the frequency (pitch) of the sound.
Rapid fluctuations in sound pressure levels are detected by our sensitive eardrums and then transmitted to the brain, which then interprets these fluctuations as sound.Ī speaker cone creates these rapid fluctuations in sound pressure levels by moving backwards and forwards at a specific frequency.
Sound waves like the ones shown further down this page are simply a representation of changes in sound pressure levels that take place over time.